1. Technical Field
The field of the present invention generally relates to a document-processing office machine such as a printer, copier, sorter, document feeding device or a document stacking device. More particularly, the invention relates to an office machine in which single documents of different types can be conveyed.
2. Background Art
In an office machine it is often desirable to transport a document with low force and in which, during the conveyance of the documents to an alignment edge, the documents are not damaged or destroyed. This is desirable even though the document conveyance system continues to act on the document for a specific time after the document has run up to the alignment edge.
Devices for conveying single documents onto document stacks are known. For example, these devices may operate with flexible driving elements such as rubber belts which loosely rest on and drive the documents. Other known devices have rotating fingers comprising flexible materials with a high coefficient of friction which contact and rotatably drive the documents. Yet other known devices have special form wheels with a multiplicity of finger-like structures which are disposed symmetrically at the circumference.
In these known solutions it is disadvantageous that no constant and predetermined conveying speed can be attained since the conveying speed, in particular in the case of solutions involving fingers and form wheels, depends strongly on the axis interval between the driving shaft from the document. It is also a disadvantage that, due to the flexibility of the conveying media, the phase relation between the drive and the document movement is indeterminate.